Automatic telephone-exchange system.



G. DEAKIN.

AUTOMATIC TELEPHONE EXCHANGE SYSTEM. APPLICATION FILED MAR. 27. 1912.

Patented June 6, 1916.

WITYVERXYES n 'E' s'rn.

GERALD DEAMN, OF SfxN FRANCISCO, CALIFORNIA.

ASSIGNQIL, BY E312.

\ E ASSIG N- MENTS, T \VESTERN ELECTRIC COMPANY ZNCGRPOB-ATED. A CCRP'GRATIOZF 02 NEW YORK.

Application filed March 27,

T 0 all 'whom it may concern Be it known that I, GERALD DEAKIN, a citizen of the United States of Amer 21, and

a resident of San Francisco, San Francisco 5 county, California, have invented a new and useful Improvement in Automatic Telephone-Exchange Systems, of which the fol.- lon-ing a specification.

My invention pertains an improved party line ringing circuit, applicable to telephone systems in general, with particular reference to automatic. telephone sys ems.

In the automatic telephone systems now in successful commercial operation, it is the. common practice to terminate the line from the subscribefis station at the cen'ral oflice, either directly or indirectly, on a selector switch or other similar piece of switching apparatus. The function of the selector is to automatically extend the connection fro ,1 the calling station in response to impulses originating at said calling station, to the proper switch which makes the final. connection with the called line. This latter switch is commonly known as a connector switch or simply a connector. The form of con nector now in general use is arranged to se lect the last two digits of a number, all preceding digits being; selected by selectors? Thus, in an automatic: telephone exchange of a capacity requiring the use or" four digits in. all numbers, the first two digits in every case would be selected by first and second solectors respectively, and the last two digits by a connector.

Where party line service in on automatic telephone excl'iangc is desired, it now customary to provide a. plurality classes of connectors, there being as many classes of connectors as there are stations on a party line. Each class of connector is arranged to call its corresponding class of station only, and, each party line, by the proper )Z- l tipling, of its contacts in the comic; or 0 banks is made available to as many classes of connectors as there are classes of stations. Therefore, by assigning such numbersto the various stations on a party line as will cause the proper connector to be picked up automatically during calling, no special operating methods are rei' uircd on the part of the callin subscriber in establishing a connection with any' one of the stations on a party line.

As previously stated, the connector selects AUTOIflA'lIC TEL-KPH HE-EXCHANGE SYSTEM'.

Specification of Letters Patent.

1P2 tented fnne 6, 1918. 1912. Serial No. 686,579.

the last two digits of a number and selectors all preceding digits. erefore, it roar he saw that the purpose or 1e tors is to se lect automatically, the pro 'ier conn' 'lhe selectors now in common use are ar ranged to select an idle trunk in anyone of ten groups of trunks, rnnniu to other selectors or to connectors. The first group corresponds to the figure Land selected by mg one (1) on the suhscuoers station dial: 8 the second group to the figure and so on to the tenth group which corresponds to the figure 0. Since the connector uiust select the last two digits of every number it follows that each connector must have access to at least one hundred lines, e. 6, Oil to $19. To illustrate the present practice more folly, consider for eizarnple, par line svsteni in which there are four stat s on .5 line. In this case, there would be of connectors, each class haw-i r o to the same group of lines. This Womd he acconr plished by multipling the connector bani: contacts, the sets of contact being numbered from 00, Ol to 98, 99, before each class of connector. To permit the selection of th proper connector, it only or 1- nect each class of connector groups of bank contacts or le ceding selectors. Thus. in case of the four party line class of connectors might he first group of trin'ik contacts, on tors, and the sect class h second group of contact this manner, line 01., ezomuisle, would be selected whenever the following-lest three were calle '31. i, ,01, pro

:e ing iii cons-i to the selec- DB 'csponding line, would he called.

In my impr red party line ringii 0 i=2; curt, connect the different lerels or selector contacts l to in e pr paragraph, to dillcrcnt hr; cgmnector, instead of to di connectors. in this we :11 connector mar he made to call any sta"o on a. part-r lin the selection being controlled by the calling line branch over which the connector opcrated.

w asal n in ie accompany mg ciavungs, F1 tire l 31;

and 2 illustrate my improved ringing circuit. In the first figure a circuit arranged for two stations ona line is shown. In the second figure, a circuit arranged for three or more stations on a line is shown.

In these drawings no attempt has been made to show the arrangement of apparatus by means of which a connection is established. My improved ringing circuit is not involved in the establishment of a eonnection between the calling line and the called line terminals. My improved circuit involves merely the ringing of the called station after the selectors and connector have properly established the physical connection. A complete description of the op eration of a selector and party line connector will be found in a patent granted in my name, No. 1,024,18 t dated April 23, 1912.

In Fig. 1, A represents a station on what we may designate the calling line, and B and C two stations on what we may designate the called' line.- VL and RL are wires of the calling line connecting the callin station A, through selectors and such ot er switches (not shown) as may be involved in the connection to the calling branch of the connector at D or at D as the case may be. N represents a line relay controlled by ringing key 3 at the calling station. Line relay N controls the ringing relay P. Calling branch D of the connector includes a relay 0, which relay controls the character of ringing power delivered to relay P. VC and 13C represent the two wires of the called line, 5 and 7 represent condensers in series with ringers 6 and 8 at stations B and C, respectively. Q and R represent condensers connecting the calling and called branches of the connector.

In Fig. 2, A represents the calling station and F, G and H the called stations Relays N', P, O and 0 correspond to relays N, P and O, in Fig. 1. J, J and J represent the different calling branches of the connector, each of which may be selected by the calling station A, depending upon which row or level of the preceding selector is called.

The operation of my improved ringing circuit,is as follows, reference being made first to Fig. 1 of the accompanying draw- Station A, as previously stated, can call/automatically, either station B or C. To call station B, station A would call such a number as would automatically effect a connection with the connector through branch D. To call station C, station A would call such'a number as would automatically effect a connectiop with the connector through branch D. A'is connected through branch D and ringing key 3 at station A is depressed a circuit is established from earth 2-, through 3, 4,

When station.

W, V, winding of N, battery 1 to earth again at 2. The result is that relay N is energized, thereby closing a circuit from earth 2, through 15, 16, winding of P, l to 2. Relay P thus energized, causes contact spring 12 to break contact at 13 and make contact at 1% and contact spring 10 to break contact with 9 and make contact with 11. The operation of relay P causes the bell at station B to ring, a circuit being established t from earth 2, through ringing generator S, 17, 18, H, 12, wire VG of calling line through condenser 5, ringer 6 to earth 2. Ringer 8 at station C receives no current from the ringing generator S, and for this reason remains silent. Should station A wish to call station C, connection would be made with the called line through branch D. Thus, when the ringing keyat station A is depressed, a circuit is established from earth 2, through 3, 4, line wire VL to wire V of the branch D, through winding of relay 0 and relay N to battery 1 and earth 2. Both relays O and N are now energized. The energizing of relay N causes relay P to operate as previously described. .The result is that ringing generator current. is supplied to the calling line in such a man-. ner as to operate the ringer at station C but not at station E, a circuit being established in this case from earth 2, through ringing generator 8,20,21, 11, 10,eondenser 7 rin fer 8 to earth 2. The operation of relay I) previously referred to, causes contact spring 18 to break contact with 17 and me make contact with 19 and. swinging spring 21 to break contact with 22 and make contact with 20.

It will be noted that when ringing generator current is supplied to one side of the line, the other side of the line is grounded. The object of this is to shunt out the ringer and condenser at the station not. being called, so that should the called station answer while ringing current is being suplied to the line, the current passing through the called stations telephone set, now bridged across the line, to the opposite side of the line, will go direct to earth at the central ofiice rather than through the com denser and ringer to earth at the other sta-' tion on the line. I,

In the circuit just described, reference has been made to the well-known two-party line arrangement in which the ringer at one station is bridged from-one side of the line to ground and at the other station from the other side of 'the line to ground. 'VVhere more than two stations on a line are desired, it is now customary to resort to special gen: erators and special ringers, the ringers be ing so designed as to operate on current from their corresponding generator only. My improved circuit arranged for the use of such ringers and ringing machines is Relay N causes relay P *tor S is supplied to showh in Fig. 2. The principle involved in the operation of this circuit is the same as in the circuit shown in Fig. 1. Here the calling station A has access to three or more branches on the calling line side of the connector. Three branches are shown in Fig. 2 at J, 1 and J respectively. As before stated, the calling station may effect a connection with any branch by calling the proper row or level on the preceding selector. For example, connection with branch J may be effected by calling 1301, and with J by calling 4401 and with J by calling 4501. To call station F, station A would select calling branch J. To call station G calling station A would select branch J. To call station H calling station A would select branch J The different branches, as before stated being selected automatically when calling the station number. Assume station A to be connected with called line through branch J. lVhen ringing key 3 is depressed a circuit is established from earth 2, through 3, 4, 'VL, V, winding of N, 1 to 2. Relay N is now energized and closes a second circuit from earth 2, through 23, 24, winding of P, 1 to 2. Relay 1" now operates, causing contact spring 25 to break contact with 26 and make contact with 27 and contact spring 28 to break contact with 30 and make contact with 29. Current is now caused to flow from one pole of ringing generator S through 38, 87, 32, 31, 27, 25, wire VC' of called line, through con densers 43, 45, 47 and ringers 4-1, 16 and 48 at stations F, G and H respectively, back over wire RC of called line through 28, 29, 34, 35, 40, 41 to the opposite pole of ringing generator, S. i s previously stated, the ringers are so designed as to operate on current from their corresponding generator only. Therefore, ringer 44 at station F, which responds to current from generator 8, operates, the remaining ringers, 46 and 48, remaining silent. To call station G, station A in calling would automatically sclect the called line through branch J When the ringing key at calling station is depressed, relays O and N are energized.

to operate as previously described. The result is that current flows through the condensers and ringers on the calling line from generator S causing Y the operation of ringer 46 which responds to current from generator S Ringers 44 and 48 remain silent. To ca ll station H, station A. in calling would. automatically select the called line through branch J When the ringing key at station A is depressed, re lays O and N operate. Relay N as we viously stated. causes the operation of relay The result is that currentfrom genera the' calling line with 48 at station H, which the result that ringer from generator S opresponds to current crates, while ringers 44 and 46 remain silent.

In the preceding paragraphs, reference has been made to automatic systems employing a ringing key at the subscribers stations. By suitable modifications, my improved ringing circuit may be applied to those systems in which a ringing key is not required, that is, to those systems where the ringing of the called subscriber is done automatically, after the desired station numher has been called, the bell at the called station, ringing party answers or until the calling party replaces receiver upon switchhook. in case called party does not answer. In such systems as these, as in in the system described in the preceding paragraphs, the relays O, O and U as the case may be, controlling the ringing generator supply, are placed in series with the calling line, substantially as shown and described.

By proper adaptation the lection of the character rent to be supplied to the called line, depending upon the use of a plurality of call ing line branches, may be readily applied to trunking systems in manually operated exchanges. In such systems as these, the'operator making the trunking connection to the called station, would have access to many branches of the trunkin circuit as there are classes of stations to e called.

Having thus described my invention, what I claim as new and desire to secure by United States Letters Patent, is:

1. In an automatic telephone system, a connector having party lines terminating thereon, said connector being reached by a plurality of paths, and means for selectively ringing on said party lines, the character of the ringing being controlled by the path over which the connector is reached.

2. In a telephone-system, a calling line, a called line, a plurality of stations on said called line, a means of completing connections between said calling and said called lines, said. means having one called line branch and a plurality of calling line branches, any of which latter branches may be selected by said calling line. a ringer at each station connected with said called line, arranged to operate only when supplied with a particular kinder arrangement of current. a means of supplying the proper arrangement or kind of current to operate the ringer at any one of said stations connected to said called line. depending upon which of said calling line branches of said means of com plating connections between said calling and said called lines. is selected by the calling line. 7

In. an automatic telephone system, a calling line, a called li e, a plurality of statmns on said called line, a connector for principle of seof the ringing curcompleting connection between said calling and said called lines, said connector having one called line branch and a plurality of calling. line branches, any of which latter 5 branches may be selected by said calling line, a ringer at each station connected with said called line, arranged to operate only when supplied with a particular kind or arrangement of current, a means of supplying'the proper arrangement or kind of current to operate the ringer at any one of said stations connected/to said called line, depending upon which of said calling line branches of said connector is selected by the calling line.

5 4. In an automatic telephone system, a calling line, a called line, a plurality of stations on said called line, a connector for completing connection between said calling and said called lines, said connector having one called line branch and a plurality of calling line branches, any of, which latter branches may be selected by said calling line, a ringer at each station on said called line, arranged to operate only when supplied with a particular kind or arrangement of current, a relay or plurality of relays in series with part or all of said calling line branches of" said connector, adapted to supply the proper arrangement or kind of current to operate the ringer at any one of said stations connected to said called line, depending upon which of said calling branches of said connector is selected by the calling line.

5. In an automatic telephone system, a

calling line, a called line, two stations on said called line, a connector for completing connection between said calling and said called lines, said connector having one called line branch and two calling line branches, either of which may be selected by said calling line,

av ringer at each station of said called line,

one bridged from one Wire of said called line to earth and the other bridged from the opposite wire of said called line to earth, a

relay in series with one of said calling line branches of said connector, adapted to supply current to either side of said called line,

depending upon which of the said calling.

line branches'of said connector is selected by said calling line.

6. In a partydine telephone system, a sub scri'hera line, a connector for seizing said line, means for extending connection to said connector, a plurality of ringing generators,

a relay for controlling each of said generators, and means for energizing one oi ellil relays upon the completion of the connection to the connector.

7. In a party-line telephone system, a sat scribers line, a connector for seizing said line, means for extending connection to said connector, a plurality of ringing generators, a relay for relays bein and means connected in parallel circuits, or energizing one of said relays "calling and a called Billmfjlllin iiectori'pr controlling each generator, said =--to control the associated generator upon the being dependent upon the contact of the selector switch employed for extending the 3 connection to the connector.

In a party-line telephone system a calling and 1 called snbscribers line, means including a selector and a connector switch for establishing connection between said lines, 35 said selector comprising a bank of contacts arran ed in levels, said connector bein connected with contacts of a plurality 0% said levels, a plurality of ringing generators for supplying current to the called line, means for selecting one of said generators, the generator selected being dependent upon the level of the selector employed in estending the connection to the connectorvv 10. In a party-line telepho e system, a calling and a called is 'il line. con nector for seizing the liillfim line, and means including a selector for extending connection from the calling line to said connector, said selector including a. plurality of banks of contacts, multiple connections from a plurality of contacts of one of said banks to said connector, and independent connections from corresponding contacts of a second of said banks to said connector. 105

11. In a party-line telephone system, a calling and a called subscribers line, a connector for seizing the called line, and means including a selector for extending connection from the calling line to said connector, said selector including a plurality of banks of contacts, multiple connections from a plurality of contacts of one oi said haul, sai" connector, independent cone corresponding contac banks to said. r ing gen rate rent to the can? i over said ii ing one of l 12. In a party-line te ing the called line, and means including a selector for extemling coiinectgton from the calling line to said connect-ta, said selector including a plurality of banks of contacts arranged in levels, multiple connections between corresponding contacts eta plurality of levels of one or more of said contact banks to said connector, wherebv connection may he established through a plurality of said leves. independent e0nneetions from the corre pomling contacts of another of said hanks to said connector. a plurality of ringing generators for supply ing ringing current to the called line. and means controlled er said independent connections for selecting one of said ringing generators.

1?. In a party-line telephone system, a calling and :1 alled snhscrihens line, a con nector for seizing the called line. and means including a selector for extending conneetion from the calling line to said connector, said selector including a plurality of hanks of contacts. multiple connections l'rom a plurality of contacts of one of said hanks to said connector. independent connections from corresponding contacts of a second of said banks to said connector. a plurality of ringing generators in said connector for supplying ringing current to the called line, a relay in each of said independent connections for controlling the selection of one of said generators. and means for energizing one of said relays \vhen connection is made with said connector, the relay energized being dependent upon the level of the selector switch employed in extending the connection.

H. In a party-line telephone system, sul

scrihers lines divided into grou s, a onnector having motion in one plane to select groups and motion in a plane at rightangles thereto to rind a line in the selected group for seizing a called suhserihefs line, means tor extending connection to said con ncctor. a plurality of ringing enerators, a relay for controlling each of said generators, and means for energizing one of said relays upon the completion of the conn ction to the connector.

1?. ln a partv-line telephone s \'stei11, snbscriliers' lines divided into groups, a eonnector having motion in one plane to select groups and motion in a plane at right angles thereto to find a line in the selected group for seizing :1 called subs riber's line, means for extending connection to said eonnector. a plurality of ringing generators, a relay for controlling each generator said relays heing conne ted in parallel circuits, and means (or energizing one of said relays to control the a socnited geimrator upon the completion of the conncctioi'i to the eonnector.

Signed by me at San Francisco this lith day of June, 1911.

GERALD DEAKIN. 'itnesses:

Parmxi; .l'. (:meon, E. A. McCANX. 

